Add project settings support

[s7726]

Please consider adding project level settings support.

Each project may have it's own method of running/configuring tests etc. Rather than configuring this globally.

Example: https://github.com/jonlabelle/SublimeJsPrettier/blob/40152c846f0808c34cd156ed02f8588e77e32ed3/jsprettier/sthelper.py#L34